GB1191138A - Thermoelectric Assemblies - Google Patents

Abstract

1,191,138. Thermoelectric devices. T. M. ELFVING. 27 Oct., 1967 [27 Oct., 1966], No. 48998/67. Heading H1K. A thermoelectric assembly comprises an aluminium heat exchanger pressed against a junction bridge of a thermocouple and prestressing the semi-conductor elements of the thermocouple, the heat exchanger being thermally and electrically connected to the junction bridge but not forming a significant part of the current path. In a first embodiment, Fig. 1A and Fig. 1B (not shown), a sub-assembly comprises two annular bismuth telluride bodies 211 and 212 of opposite thermoelectric types soldered to a nickel-plated copper junction bridge 213 and to two annular end plates 214, 215 of the same material. A plurality of such assemblies are arranged on opposite sides of pipe sections 216, 217 which form bridges between the end plates of the oppositely positioned assemblies. The pipe sections are connected by insulators 218 to form a fluid flow conduit. Aluminium heat exchangers, in the form of pairs of tubes provided with fins 222, are placed in contact with each of the junction bridges 213 and the assembly is compressed by means of stainless steel bolts 221 acting between insulating members 224, 225. In a modification, Fig. 3 (not shown), the pipe sections (216, 217) are replaced by copper tubes extending coaxially with the compression rods between the ends of the upper and lower sub-assemblies. The copper tubes are provided with external fins, which may be tapered in cross-section. In a second embodiment, Fig. 2 (not shown), a single line of sub-assemblies are connected in series by further bridge members which are soldered across, or are pressed against, the end plates of adjacent assemblies. Aluminium heat exchangers are pressed against each bridge member. If the further bridge members form pressure contacts to the end plates the surfaces may be treated with a gold flash over silverplating. The junctions between the semiconductor bodies and the junction bridges may also be pressure contacts, the surfaces of the bodies being provided with a nickel plating, silvering, and a gold flash. The semi-conductor bodies may be held in position by a plastic frame. In a modification, Fig. 4 (not shown), each sub-assembly comprises a pair of blocks of semi-conductor material joined by a disc shaped junction bridge and having rectangular end plates. The further bridge members are also disc-shaped, and the heat exchangers comprise a finned single tube clamped against each bridge. In a further modification, Fig. 5 (not shown), the further bridging members and their associated heat exchangers are replaced by pipe sections connected by insulators to form a fluid conduit. In another modification, Fig. 6 (not shown), pipe sections extend transversely to the assembly and form bridges between the ends of each sub-assembly and corresponding ends of a second series of sub-assemblies, inverted relating to the first series, the bridge members of which are also contacted by finned aluminium heat exchangers.